Identification of soluble WSX-1 not as a dominant-negative but as an alternative functional subunit of a receptor for an anti-Alzheimer's disease rescue factor Humanin.

Humanin (HN) inhibits Alzheimer's disease (AD)-relevant neuronal death and dysfunction, by interacting with a receptor (s) involving ciliary neurotrophic factor receptor alpha (CNTFR), WSX-1, and gp130. It remains unknown whether this complex is the sole HN receptor that mediates HN-induced anti-AD activity. We here report that an alternatively spliced WSX-1 isoform, encoding an extracellular 270-amino-acid region of WSX-1 with cytokine-binding regions (named soluble WSX-1; sWSX-1), is expressed in neuronal cells lacking function of full-length WSX-1 and enables HN to rescue AD-relevant death. This result suggests that CNTFR/soluble WSX-1/gp130 behaves as an alternative functional HN receptor.